The first thing is to visit a gynecologist or doctor of your choice and ask for advice. It is also possible to go to the hospital or Family planning center. Also the Public Welfare Centre CPAS in French and OCMW in Dutch can offer some advice. There is one in every municipality and they are listed in the telephone directory.
For more information: http://bruxelles-j.be/bruxelles-j/
https://www.zanzu.be/en/themes/family-planning-and-pregnancy
To look for a family planning center in Brussels or Wallonia: http://www.loveattitude.be/
In Flanders: http://abortus.be/_en/home/index.php
The association “Tremplin Saie” also helps teenage mothers in Belgium: www.tremplinsaie.be